Gaming machine and method for displaying symbols

ABSTRACT

A gaming machine comprises a display unit that displays video reels using computer graphics. Symbols are moved and stopped on each video reel. A game controller unit selects a type of symbols and an arrangement of symbols at random, and provides a player with an award if a winning combination appears on a payline in the arrangement of symbols and the player has placed a bet on the payline. A display controller unit causes the display unit to move symbols on each video reel, and then stop symbols in the arrangement. The display controller unit further causes the display unit to change a symbol of the selected type to a special symbol while moving symbols. Special symbols appear in a prominent form, e.g., in a background color complementary to a background color of other symbols, or in a metallic color, or in a blinking, flashing, or sparkling pattern.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a gaming machine that is installed in acasino or the like, and in particular conducts a slot game.

2. Background Information

Gaming machines such as slot machines, poker machines, fruit machines,and the like generally attract enormous popularity from players incasinos. Such a gaming machine displays an arrangement of symbols on thefront thereof, and changes the types of symbols in the arrangement atrandom. A player guesses on which payline in the arrangement of symbolsa winning combination will appear, and then places a bet on a desiredpayline before symbols are changed in the arrangement. If a winningcombination appears on the payline where the player has placed a bet,the player will win an amount of a payout that depends on the amount ofthe bet and the type of the winning combination.

This type of gaming machine is generally equipped with mechanical reelsthat are coaxially arranged and allowed to independently spin byrespective motors. Symbols are permanently displayed, e.g., printed onthe circumferential surfaces on each reel in a predetermined order.Mechanical reels repeat spins and stops, and thereby change visiblesymbols at random. Alternatively, this type of gaming machine may beequipped with an electric display device, and symbols are arranged ingraphic form, i.e., a video reel reproduced on a screen of the electricdisplay device. Video reels are changed to look like mechanical reelsrepeating spins and stops, and thereby change visible symbols at random.There is also a mechanical reel with one or more electric displaydevices mounted on the circumferential surface of the mechanical reel.Symbols are displayed in graphic form on a screen of the electricdisplay device.

Most players prefer a gaming machine that can provide a larger amount ofpayout. The upper limit of payout generally depends on a total number ofwinning combinations that can appear in an arrangement of symbolsvisible on reels. Mechanical reels have a limited number of symbol typesmainly because of their sizes. In order to increase the upper limit ofpayout, a gaming machine with mechanical reels changes visual effectsadded to visible symbols in stopped positions, e.g., colors or patternof illumination thereof in order to increase the number of symbol types.This can also excite a player by raising his/her expectations forwinning. On the other hand, video reels have no limited number of symboltypes in principle. However, video reels often change visual effectsadded to visible symbols in stopped positions in order to change typesof the visible symbols and thereby raise players' expectations forwinning. On video reels, graphic form of symbols can enhance flexibilityand variety of the changes in visual effect, in addition to colors andpattern of illumination of visual symbols.

In order to attract a larger number of players to such gaming machines,it is desirable to be able to further enhance flexibility and variety ofchanges in visual effect added to visible symbols. However, prior artgaining machines limit changes in visual effects to visible symbols instopped positions in order to produce the changes in a recognizablemanner. However, the changes after stop of reels tend to increase anamount of time per game round. This prevents the changes from achievinghigher degrees of flexibility and variety, since excessively longer timeper game round is not attractive to players.

In view of the above, it will be apparent to those skilled in the artfrom this disclosure that there exists a need for an improved gamingmachine that can change visual effects added to visible symbols, notonly with higher degrees of flexibility and variety, but also in amanner more attractive to players. This invention addresses this need inthe art as well as other needs, which will become apparent to thoseskilled in the art from this disclosure.

SUMMARY OF THE INVENTION

A gaming machine according to the present invention comprises a displayunit, a console unit, a game controller unit, and a display controllerunit. The display unit is configured to display symbols using computergraphics. The symbols are arranged in a plurality of columns, and movedand stopped on a column-by-column basis. Note that the display unit maydisplay all symbol columns, i.e., video reels on a single screen, oralternatively each symbol column on a screen wound around thecircumferential surface of a mechanical reel. The console unit isconfigured to accept monetary data and an instruction from a player toplace a bet. The game controller unit is configured to execute a gameprogram, and thereby control the following game functions: using themonetary data as a bet in response to the instruction; selecting a typeof symbols at random; determining an arrangement of symbols at random;retrieving a winning combination from the arrangement of symbols; andproviding the player with an award depending on the bet and the winningcombination retrieved from the arrangement of the symbols. The displaycontroller unit is configured to cause the display unit to move symbolson a column-by-column basis, and then stop symbols in the arrangementselected by the game controller unit. The display controller unit isfurther configured to cause the display unit to change a symbol of thetype selected by the game controller unit to a special symbol whilemoving symbols.

This game machine selects a type of symbols at random, and changessymbols of the selected type to a special symbol while moving symbols.This not only increases a number of symbol types, thereby raising anupper limit of payouts, but also excites a player by raising his/herexpectations for winning, while symbols are moved, preferably, during aspin of reels.

The game controller unit is preferably configured to interpret thespecial symbol as a wildcard symbol. In this case, changes of symbols ofthe selected type to the special symbol are actually advantageous to aplayer, since the player has a good chance of winning.

The display controller unit is preferably configured to cause thedisplay unit to change a background color of the special symbol to acolor complementary to a background color of other symbols while movingsymbols. This can change symbols of the selected type to the specialsymbol in an easily recognizable manner. Alternatively, the displaycontroller unit may be configured to cause the display unit to displayonly the special symbol in a metallic color while moving symbols. Thedisplay controller unit may be configured to cause the display unit todisplay the special symbol in a blinking, flashing, or sparkling patternwhile moving symbols.

The display controller unit is preferably configured to provide a higherprobability of displaying candidates for a type of symbols to be changedto a special symbol at adjacent positions while the display unit movessymbols, than other types of the symbols. In this case, there is a goodchance that a group of special symbols appear in a visible positionwhile symbols are moved. This can cause a player to more reliably noticethe changes of the selected symbol to a special symbol.

The display unit preferably includes a region in which candidates for atype of symbols to be changed to a special symbol are displayed in astatic graphic form. In this case, the display controller unit ispreferably configured to cause the display unit to change the candidateof a type has been selected by the game controller unit to a specialsymbol in the region while the display unit moves symbols. A player canconfirm an appearance and a type of a special symbol through the displayin the region.

The game controller unit is preferably configured to select two or moretypes of symbols at random. In this case, the display controller unit ispreferably configured to cause the display unit to change symbols of thetypes selected by the game controller unit to special symbols in turnwhile moving symbols. This visual effect can excite a player bygradually raising his/her expectation of winning while moving symbols.

These and other objects, features, aspects and advantages of the presentinvention will become apparent to those skilled in the art from thefollowing detailed description, which, taken in conjunction with theannexed drawings, discloses a preferred embodiment of the presentinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring now to the attached drawings which form a portion of thisoriginal disclosure:

FIG. 1 is a perspective view of the appearance of a gaming machineaccording to an embodiment of the present invention;

FIG. 2 is a block diagram of the hardware configuration of a gamecontroller unit included in the gaming machine shown in FIG. 1;

FIG. 3 is an example of a symbol arrangement in stopped positionsdisplayed on a screen of the gaming machine shown in FIG. 1;

FIG. 4 is another example of a symbol arrangement in stopped positionsdisplayed on a screen of the gaming machine shown in FIG. 1;

FIG. 5A is an example of a first state of moving symbols displayed on ascreen of the gaming machine shown in FIG. 1;

FIG. 5B is an example of a second state of moving symbols displayed on ascreen of the gaming machine shown in FIG. 1;

FIG. 5C is an example of a third state of moving symbols displayed on ascreen of the gaming machine shown in FIG. 1;

FIG. 6A is a first half of a flow chart of a game round conducted on thegaming machine shown in FIG. 1; and

FIG. 6B is a second half of the flow chart of a game round conducted onthe gaming machine shown in FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

A selected embodiment of the present invention will now be explainedwith reference to the drawings. It will be apparent to those skilled inthe art from this disclosure that the following description of theembodiment of the present invention is provided for illustration onlyand not for the purpose of limiting the invention as defined by theappended claims and their equivalents.

A preferred embodiment of the present invention is a video gamingmachine preferably installed in a casino. Referring to FIG. 1, thegaming machine comprises a box-shaped cabinet 1 with an openable andclosable front panel 2. Three display units 3A, 3B, and 3C are mountedon the upper portion, the middle portion, and the lower portion of thefront panel 2, respectively. A coin slot 5, a bill slot 6, and variouspush buttons 8 are mounted between the middle display window 3B and thelower display window 3C. A coin chute 9, a coin tray 10, and a speaker11 are installed below the lower display window 3C.

The three display units 3A, 3B, and 3C each include a flat displaydevice preferably, or a liquid crystal display device more preferably.The display units 3A, 3B, and 3C reproduce various images, for example,images for use in decoration and advertisements, e.g., the logo of agame developer, images for use in visual effects in games, andvisualized information on games, e.g., pay tables, illustrations of gamecontent, and jackpot values. In particular, the middle display unit 3Bdisplays preferably five video reels, i.e., five symbol columns, thenumber of available credits of a player, the amount of a bet, and theamount of an award that the player has won.

The coin slot 5 and the bill slot 6 allow a player to enter coins andbills thereinto, respectively. The entered coins and bills are countedby a counter and validated by an acceptor. The counter and the acceptorare installed inside the cabinet 1. The total amount of the validatedcoins and bills are displayed on the middle display unit 3B as creditsavailable to the player. A coin hopper installed inside the cabinet 1stores a large number of coins and bills together with the coins andbills entered by the player. The coin hopper discharges coins equivalentto credits that a player has won on a game through the coin chute 9 intothe coin tray 10. Note that the gaming machine may support aticket-in/ticket-out system, i.e., accept and print a bar-coded paperticket. A bar code printed on the ticket represents monetary dataavailable to a player.

The push buttons 8 allow a player to operate the gaming machine. Forexample, by using the push buttons 8, a player can select one or morepaylines on the video reels, and place a desired amount of a bet on eachselected payline. The player then pushes a spin button included in thepush buttons 8 to cause the video reels to start spinning, i.e., symbolsto move in the vertical direction. If an arrangement of stopped symbolsincludes a winning combination on any of the selected paylines, theplayer will win an award depending on the amount of the bet and the typeof the winning combination. The player will be allowed to push acash-out button included in the push buttons 8, and then receive coinsequivalent to the player's credit from the coin chute 9. The pushbuttons 8 are preferably lamp buttons, which each include alight-emitting device and lights up when pushed by a player or used inlighting effects during game play.

The speaker 11 is installed inside the cabinet 1, and generates voiceannouncements and sound effects during game play.

The above-described components of the gaming machine are preferablycontrolled by a game controller unit that is preferably installed insidethe cabinet 1. Alternatively, the game controller unit may be separatedfrom the cabinet 1, and connected through a network to the components ofthe cabinet 1.

Referring to FIG. 2, the game controller unit includes a CPU 21, a ROM22, a RAM 23, a credit controller unit 24, a console unit 25, a payoutcontroller unit 26, a random-number generator unit 28, a lightingcontroller unit 29, a sound controller unit 30, and a display controllerunit 31.

The CPU 21 runs various programs and thereby controls other componentsof the game controller unit according to instructions and data acceptedby the console unit 25. The ROM 22 stores programs and databases used bythe CPU 21. The RAM 23 temporarily stores variables, parameters, and thelike that are used by the CPU 21.

The credit controller unit 24 manages the amount of player's credits,which is equivalent to the amount of coins and bills counted andvalidated by the counter/acceptor 24A. The console unit 25 monitors thepush buttons 8 and accepts various instructions and data from the pushbuttons 8. The payout controller unit 26 changes player's credits tocoins, bills, or other monetary data by using the coin hopper 26A or thelike.

The random-number generator unit 28 generates and outputs randomnumber(s) to the CPU 21. The random number will be used to randomlyselect an arrangement of stopped symbols and a type of symbols to bechanged to a special symbol.

The lighting controller unit 29 controls lighting devices 29A installedin the three display units 3A, 3B, and 3C, the push buttons 8, and otherlumps mounted on the cabinet 1 during game play. The lighting controllerunit 29 thereby causes the lighting devices 29A to blink and/or changebrightness and color in specific patterns in order to produces lightingeffects. The sound controller 27 controls the speaker 11 to output voiceannouncements and sound effects during game play.

The display controller unit 31 controls the three display units 3A, 3B,and 3C to display various images on screens preferably by using computergraphics. The display controller unit 31 in particular controls videoreels displayed on the middle display unit 3B by using computergraphics. FIG. 3 shows an example of a game screen 40 displayed on themiddle display unit 3B. Preferably, five video reels 41A-41E arearranged on the game screen 40. Note that the number of video reels maybe changed from five to other number, e.g., three. On each video reels41A-41E, preferably three or more symbols 42 are repeatedly moved andstopped in a vertical direction. During moved, different types ofsymbols 42 appear at random or in a predetermined order. This action ofsymbols 42 is often referred to as “spins of video reels”. After apredetermined time has elapsed, symbols 42 will be stopped in anarrangement that the game controller unit randomly selects at a start ofeach game round. In stopped positions, symbols 42 are preferably alignedon one of three horizontal lines. In this case, all horizontal lines andslanted lines are preferably selectable as paylines. Alternatively,symbols may be stopped in a honeycomb arrangement. For example, if threeor more symbols of the same type are aligned on a selected payline, aplayer will win an award depending on a bet placed on the payline andthe type and number of the symbols aligned on the payline. The gamescreen 40 also includes a number of available credits, an amount of abet placed at a game round, and an amount of a payout won at the gameround.

In addition, the game screen 40 includes preferably four small regionsin which four candidates 43A-43D for symbol types to be possibly changedto a special symbol are displayed in a static graphic form. Note thatthe number of the candidates 43A-43D may be changed from four to othernumber. The game controller unit randomly selects zero or morecandidates 43A-43D to be changed to a special symbol at each game round.The special symbol is preferably interpreted as a wildcard symbol. Thespecial symbol may have a different function, e.g., of indicating abonus game or an extra payout to be provided to a player when appearingin an arrangement of stopped symbols. Among the candidates 43A-43D, oneor more selected as being changed to special symbols will be prominentlydisplayed on the respective small regions. Furthermore, symbols of thesame type as the selected candidates will appear in a prominent form onthe video reels 41A-41E. Referring to FIG. 4, three candidates, i.e., across symbol 43A, a circle symbol 43B, and a star symbol 43C areselected as special symbols 44A, 44B, and 44C, respectively. When thespecial symbols 44A-44C are interpreted as wildcard symbols, anarrangement of stopped symbols 42 shown in FIG. 4 includes a winningcombination equivalent to five “seven” symbols 42D aligned on the secondhorizontal line, in contrast to the same arrangement without specialsymbols shown in FIG. 3. Thus, the larger number of the candidates areselected as being changed to special symbols, the better chances ofwinning are provided to a player.

The display controller unit 31 causes the middle display unit 3B tochange selected candidates 43A-43C to special symbols 44A-44C whilemoving symbols 42 in a vertical direction. Preferably, the backgroundcolor of these special symbols 44A-44C is changed to a colorcomplementary to the background color of other normal symbols 42. Forexample, when the background color of normal symbols 42 is white, green,or bluish-purple, the background color of special symbols 44A-44C isblack, red, or yellow, respectively. The colors of special symbols44A-44C themselves may be changed to complementary colors. Morepreferably, colors of special symbols and their background are changedto a metallic color. Special symbols may be displayed in a blinking,flashing, or sparkling pattern by using computer-generated animation.These prominent changes in color and pattern of symbols enable a playerto easily notice appearances of special symbols 44A-44C while symbols 42are moved on the video reels 41A-41E. Note that the display controllerunit 31 preferably provides a higher probability of displaying symbols42A-42D of the same types as the four candidates 43A-43D at adjacentpositions on the spinning video reels 41A-41D than symbols of othertypes. This can also cause a player to easily notice appearances ofspecial symbols 44A-44C.

When two or more candidates are selected as special symbols, theselected candidates may be changed to special symbols at the same timewhile symbols 42 are moved. More preferably, the selected candidates arechanged to special symbols in turn while symbols 42 are moved. Referringto FIGS. 5A-5C, three candidates 43A-43C are selected in advance, andwill be changed to special symbols 44A-44C in turn. First as show inFIG. 5A, the first candidate 43A, i.e., cross symbols are changed to thefirst special symbols 44A after a predetermined time has elapsed from astart of moving symbols 42, i.e., a start of spins of the video reels41A-41E. Next as show in FIG. 5B, the second candidate 43B, i.e., circlesymbols are changed to the second special symbol 44B after anotherpredetermined time has elapsed from the change of the first candidate43A to the first special symbols 44A. Finally as show in FIG. 5C, thethird candidate 43C, i.e., star symbols 44C are changed to the thirdspecial symbols 44C after another predetermined time has elapsed fromthe change of the second candidate 43B to the second special symbols44B. In particular, a player can easily notice increase in types ofspecial symbols 44A-44C not only on the video reels 41A-41E but alsothrough the candidates 43A-43D displayed on the small regions. Note thatthe moving speeds of symbols 42 may be reduced each time types ofspecial symbols are increased. Thus, a player is gradually excited eachtime he/she notices the increase in types of special symbols 44A-44C.

Referring to FIGS. 6A and 6B, operations of the gaming machine will beexplained below in the order of the flow of a game round.

STEP S1: A player inserts coins or bills into the coin slot 5 or thebill slot 6, respectively. Then, the counter/acceptor 24A validates thecoins and bills, and counts the valid coins and bills. The gamecontroller unit reads the count and updates credit data stored in theRAM 23 to increase player's credits by the number corresponding to thecount (cf. FIG. 2). Then, the player can place a desired bet on adesired payline by using the buttons 8. The console unit 25 accepts thebet placed on the desired payline. Then, the game controller unitenables the console unit 25 to accept a cue to start spinning of videoreels 41A-41E from a spin button, one of the buttons 8. When the consoleunit 25 accepts the cue from the player who pushes the spin button 8,the game controller unit updates the credit data stored in the RAM 23 todecrease the amount of the credits by the total amount of the bets.

STEP S2: The game controller unit preferably causes the random numbergenerator unit 28 to generate a random number, and then selects zero ormore candidates for special symbols depending on the random number. Thegame controller unit preferably determines the number of symbol types tobe changed to special symbols depending on the random number. When thenumber is determined to be zero, no candidates are to be changed tospecial symbols. When the number is determined to be one, the firstcandidate, i.e., cross symbols 43A are to be changed to special symbols44A. When the number is determined to be two, the second candidate,i.e., circle symbols 43B are to be changed to special symbols 44B inaddition to the first candidate 43A. When the number is determined to bethree, the third candidate, i.e., star symbols 43C are to be changed tospecial symbols 44C in addition to the first candidates 43A and thesecond candidates 43B. When the number is determined to be four, thefourth candidate, i.e., “seven” symbols 43D are to be changed specialsymbols in addition to the first-third candidates 43A-43C. Thus, thegame controller unit selects zero or more symbol types to be changed tospecial symbols at random. Preferably, the RAM 23 stores a flag linkedto each symbol type in advance, and the game controller unit only setsthe flags linked to the selected symbol types.

STEP S3: The game controller unit causes the random number generatorunit 28 to generate five random numbers preferably. Each of the fiverandom numbers is uniquely assigned to one of the video reels 41A-41E.The game controller unit then retrieves stop positions of the videoreels 41A-41E linked to the five random numbers from respective stopposition tables preferably stored in the ROM 22. Each of the stopposition tables is assigned to one of the video reels 41A-41E, andrepresents relationship between random numbers and stop positions of thevideo reel, i.e., types of symbol columns to be displayed in staticgraphic forms on the video reel. Thus, the game controller unit selectsstop positions of the video reels 41A-41E at random, and stores datarepresenting the stop positions into the RAM 23, preferably.

The game controller unit also determines whether or not to provide anaward to the player at random in the following manner. The gamecontroller unit retrieves the five random numbers from a winningcombination table stored in the ROM 22. The winning combination tablerepresents relationship between combinations of five random numbers andawards. Here, the five random numbers are linked to the stop positionsof the respective video reels 41A-41E. Accordingly, awards are assignedto winning combinations of symbols arranged on the stopped video reels.Preferably, winning combinations are assigned to arrangements wheresymbols of the same type (and a wildcard symbol) are stopped in three ormore consecutive video reels. Types of awards depend on which types ofsymbols are repeatedly included in respective winning combinations. Notethat the ROM 22 stores different types of winning combination tablesthat include different types of special symbols. The game controllerunit has selected a type of a winning combination table in advance,preferably depending on the flags linked to symbol types. If the gamecontroller unit retrieves an award linked to the combination of the fiverandom numbers from the selected winning combination table, the gamecontroller unit then decides to provide the award to the player.

STEP S4: The game controller unit instructs the display controller unit31 to start the middle display unit 3B to spinning the video reels41A-41E, i.e., continuously move symbols 42 in the vertical direction onthe video reels 41A-41E. Each time a predetermined time has elapsed, thedisplay controller unit 31 causes the middle display unit 3B to stop thevideo reels 41A-41E one by one into the respective stop positionsselected in STEP S3. Details of STEP S4 will be described below.

STEP S5: If the game controller unit has decided to provide an award tothe player, the game controller unit then controls visual and soundeffects by providing the lighting controller unit 29 and the soundcontroller unit 30 with commands. The lighting controller unit 29 thenturns on and off the lighting devices 29A in patterns represented by thecommands. The sound controller unit 30 changes sounds reproduced fromthe speaker 11 to the sound effects represented by the commands. Afterthat, the game controller unit updates the credit data stored in the RAM23 to increase the player's credits by a payout to be provided as anaward. If instructed by the player, the game controller unit may providethe player with the payout by using the payout controller unit 26. Thegame controller unit then waits a new instruction from the player.Alternatively, the game controller unit may start a bonus round to beprovided to the player as an award.

In STEP S4, the display controller unit 31 preferably causes the middledisplay unit 3B to control spins and stops of the video reels 41A-41E asfollows (cf. FIG. 6B).

STEP S401: The display controller unit 31 initializes various parametersfor the control of the video reels 41A-41E, and in particular, sets aninteger variable N to be 0 and a time variable TIME to be 0. Inaddition, a constant REEL_NUM is set to be 5 in advance, whichrepresents the total number of the video reels 41A-41E.

STEP S402: The display controller unit 31 checks if the time variableTIME is larger than a constant REEL_STOP_TIME[N], which represents apredetermined time duration of the (N+1)-th video reel continuouslyspinning. If the time variable TIME is larger than the constantREEL_STOP_TIME[N], the process will be branched to STEP S410. Otherwise,the process will continue to STEP S403.

STEP S403: The display controller unit 31 first selects five symboltypes to be “created” for the respective video reels 41A-41E. Here, thesymbol types may be selected at random or in a predetermined order. Thedisplay controller unit 31 next accesses the RAM 23 and checks flagslinked to the selected symbol types. If any flag has been set, theprocess will be branched to STEP S405. Otherwise, the process willcontinue to STEP S404.

STEP S404: The display controller unit 31 “creates” five symbols of theselected types in a normal graphic form on the respective video reels41A-41E. More specifically, the display controller unit 31 preparesnormal image data of the selected symbol types, which represents imagesof normal symbols 42 shown in FIG. 3, in a predetermined region of theRAM 23 or another memory unit.

STEP S405: When flags linked to one or more of the selected symbol typeshave been set, the selected symbol types include one or more candidates43A-43D shown in FIG. 3. The display controller unit 31 checks if thetime variable TIME is larger than a constant CHANGE_TIME, whichrepresents the time to be required from the start of spins of the videoreels 41A-41E until a selected candidate 43A-43C is changed to a specialsymbol 44A-44C, as shown in FIGS. 5A-5C. The constant CHANGE_TIMEpreferably varies with the candidates 43A-43D, and in particular,increases in the order of the first-fourth candidates 43A-43D.Alternatively, the constant CHANGE_TIME may be the same among thecandidates 43A-43D. If the time variable TIME is larger than theconstant CHANGE_TIME for any of the selected candidates 43A-43C, theprocess will continue to STEP S406. Otherwise, the process will returnto STEP S404.

STEP S406: The display controller unit 31 first creates one or more ofthe selected candidates 43A-43C, for which the time variable TIME islarger than the respective constant CHANGE_TIME, in a “special” graphicform, i.e., a prominent graphic form as special symbols 44A-44C. Thedisplay controller unit 31 further creates symbols of the other selectedtypes in a normal graphic form. The display controller unit 31 preparesimage data of special symbols 44A-44C and normal symbols 42 in apredetermined region of the RAM 23 or another memory unit. The displaycontroller unit 31 also changes image data of the selected candidates43A-43C for use in displaying the small region to that of specialsymbols.

STEP S407: The display controller unit 31 causes the middle display unit3B to display an animation of moving images of symbols 42 for a distanceon the video reels 41A-41E by using image data of the symbols preparedin previous STEPS S404 or S406 in the predetermined regions of the RAM23 or other memory unit. Note that the display controller unit 31preferably reduces the moving speeds of the symbols 42 each time typesof special symbols are increased. In addition, if any video reels41A-41E has been determined to be stopped at STEP S410 described below,the moving speeds of symbols 42 on the video reels are graduallyreduced, and then the symbols 42 will be stopped.

STEP S408: The display controller unit 31 increments the time variableTIME by a step.

STEP S409: The display controller unit 31 checks if the integer variableN is less than the constant REEL_NUM (e.g., 5). If the integer variableN is less than the constant REEL_NUM, the process will be repeated fromSTEP S402. Otherwise, the process will continue to STEP S5.

STEP S410: The display controller unit 31 determines the (N+1)-th videoreel 41A, . . . , or 41E to be stopped. Then, symbols to be displayed inthe stop position of the (N+1)-th video reel selected in STEP S3 will becreated in order after a number of repetitions of STEP S404 or S406.After that, the symbols will be actually displayed in the stop positionof the (N+1)-th video reel at STEP S407.

STEP S411: The display controller unit 31 increments the integervariable N by 1.

The display controller unit 31 repeats the loop of STEPS S402-S411 untilthe integer variable N reaches the constant REEL_NUM, i.e., the totalnumber of the video reels 41A-41E, e.g., 5. Thus, the middle displayunit 3B displays the spins and stops of the video reels 41A-41E for agame round. In particular, the selected candidates 43A-43C areprominently changed to the special symbols 44A-44C in turn as shown inFIGS. 5A-5B.

General Interpretation of Terms

In understanding the scope of the present invention, the term“configured” as used herein to describe a component, section or portionof a device includes hardware and/or software that is constructed and/orprogrammed to carry out the desired function. In understanding the scopeof the present invention, the term “comprising” and its derivatives, asused herein, are intended to be open ended terms that specify thepresence of the stated features, elements, components, groups, integers,and/or steps, but do not exclude the presence of other unstatedfeatures, elements, components, groups, integers and/or steps. Theforegoing also applies to words having similar meanings such as theterms, “including”, “having” and their derivatives. Also, the terms“part,” “section,” “portion,” “member” or “element” when used in thesingular can have the dual meaning of a single portion or a plurality ofportions. Finally, terms of degree such as “substantially”, “about” and“approximately” as used herein mean a reasonable amount of deviation ofthe modified term such that the end result is not significantly changed.For example, these terms can be construed as including a deviation of atleast ±5% of the modified term if this deviation would not negate themeaning of the word it modifies.

While only selected embodiments have been chosen to illustrate thepresent invention, it will be apparent to those skilled in the art fromthis disclosure that various changes and modifications can be madeherein without departing from the scope of the invention as defined inthe appended claims. Furthermore, the foregoing descriptions of theembodiments according to the present invention are provided forillustration only, and not for the purpose of limiting the invention asdefined by the appended claims and their equivalents.

1. A gaming machine comprising a display unit configured to display symbols using computer graphics, the symbols arranged in a plurality of columns, and moved and stopped on a column-by-column basis; a console unit configured to accept monetary data and an instruction from a player to place a bet; a game controller unit configured to execute a game program, and thereby control game functions of using the monetary data as a bet in response to the instruction, selecting zero or more types of symbols at random, determining an arrangement of symbols at random, retrieving a winning combination from the arrangement of symbols, and providing the player with an award depending on the bet and the winning combination retrieved from the arrangement of symbols; and a display controller unit configured to cause the display unit to move symbols on a column-by-column basis, change a symbol of the type selected by the game controller unit to a special symbol while moving symbols, and then stop symbols in the arrangement selected by the game controller unit.
 2. A gaming machine according to the claim 1, wherein the game controller unit is configured to interpret the special symbol as a wildcard symbol.
 3. A gaming machine according to the claim 1, wherein the display controller unit is configured to cause the display unit to change a background color of the special symbol to a color complementary to a background color of other symbols while moving symbols.
 4. A gaming machine according to the claim 1, wherein the display controller unit is configured to cause the display unit to display the special symbol in a blinking, flashing, or sparkling pattern while moving symbols.
 5. A gaming machine according to the claim 1, wherein the display controller unit is configured to provide a higher probability of displaying candidates for a type of symbols to be changed to a special symbol at adjacent positions while the display unit moves symbols, than other types of symbols.
 6. A gaming machine according to the claim 1, wherein the display unit includes a region in which candidates for a type of symbols to be changed to a special symbol are displayed in a static graphic form, and the display controller unit is configured to cause the display unit to change the candidate of a type has been selected by the game controller unit to a special symbol in the region while the display unit moves symbols.
 7. A gaming machine according to the claim 1, wherein when the game controller unit selects two or more types of symbols at random, the display controller unit causes the display unit to change symbols of the types selected by the game controller unit to special symbols in turn while moving symbols.
 8. A method comprising accepting monetary data and an instruction from a player to place a bet; using the monetary data as a bet in response to the instruction; selecting zero or more types of symbols at random; determining an arrangement of symbols at random; retrieving a winning combination from the arrangement of symbols; displaying symbols by using computer graphics, the symbols arranged in a plurality of columns, and moved on a column-by-column basis; changing symbols of the selected type to a special symbol while symbols are moved; stopping symbols in the selected arrangement; and providing the player with an award depending on the bet and the winning combination retrieved from the selected arrangement of symbols. 